Technical Field
The present invention relates to a perhydropolysilazane making it possible to form a siliceous film with minimal defects in a manufacturing process of semiconductor devices and the like, and a composition comprising the perhydropolysilazane. Further, the present invention also relates to a method for forming a siliceous film using the same.
Background Art
In manufacture of electronic devices, especially semiconductor devices, an interlayer insulating film may be formed between a transistor element and a bit line, between a bit line and a capacitor, between a capacitor and a metal wiring, between a plurality of metal wirings, and the like. Furthermore, an insulating material may be filled in isolation trenches provided on a substrate surface and the like. Furthermore, after forming a semiconductor element on a substrate surface, a coating layer may be formed using a sealing material to provide a package. The interlayer insulating film and the coating layer are often formed from a siliceous material.
On the other hand, in the field of electronic devices, micronization of device rules has been gradually made progress, and micronization of the size of an insulating structure isolating each element incorporated into a device has been required. However, according to the progress of micronization of the insulation structure, occurrence of defects in a siliceous film constituting a trench has been increased. Hence, the problem with reduction in yield rate of electronic devices is becoming serious.
On the other hand, as a method for forming a siliceous film, a chemical vapor deposition method (CVD method), a sol-gel method, a method for applying a composition comprising a silicon-containing polymer and baking, and the like are used. Among these, the method for forming a siliceous film using a composition is often employed since it is relatively simple. To form the siliceous film, a composition comprising a silicon-containing polymer such as polysilazane, polysiloxane, polysiloxazane or polysilane is applied on a surface of a substrate or the like and baked to oxidize the silicon contained in the polymer to form a siliceous film. In such a case, a method for reducing defects in the formed siliceous film has been studied.
For example, a method for reducing defects in the siliceous film by reducing the polymeric component having an excessive molecular weight in a composition comprising a hydrogenated polysilazane or polysiloxazane (Patent Document 1), a method for reducing defects in the formed siliceous film by controlling the chlorine content in a hydrogenated siloxazane solution (Patent Document 2), and the like have been studied. However, according to the study by the present inventors, sufficient reduction of defects cannot be sometimes achieved by these methods, and therefore there has been room for further improvement.
Further, a filler comprising polysilazane and polysiloxazane having a specific elemental composition for filling a gap on a semiconductor element (Patent Document 3), a film-forming composition using a polysilazane having a specific structure (Patent Documents 4 and 5), and the like have been also studied. However, the compositions which are described in these documents are not for reducing defects in the formed siliceous film or silicon nitride film, and thus sufficient effects are not recognized from this viewpoint.